How did hereditary diseases begin in the first place?
Many hereditary diseases are actually helpful in certain environments. Sickle trait, where you have only one gene for sickle cell disease, gives people who live in malarial zones an advantage because the malarial pathogen doesn’t grow so well in them. So that is good. It’s not so good in an environment with no malaria. Science is now finding out that similar situations may have happened with other genetic diseases.
